Optical communications play a more and more important role in modern communications technologies. Light of different wavelengths needs to be split or multiplexed on an uplink, a node, and a downlink for optical transmission, to implement uploading and downloading of optical signals of different wavelengths.
In the conventional art, a method of connecting splitters in tandem, or an array waveguide grating (AWG) technology is mainly used to split or multiplex the light of different wavelengths.
In the method of connecting splitters in tandem, a filter technology is used, and by using a three-port apparatus, a light wave of a certain wavelength can be separated from an optical signal multiplexing light waves of multiple wavelengths, or a light wave of a certain wavelength can be multiplexed with an incident light wave. When light waves of multiple wavelengths are required to be separated or multiplexed, multiple three-port apparatuses need to be connected in tandem by an optical fiber. Due to the requirement for tandem connection by an optical fiber, an inherent fiber coiling space of the optical fiber causes a bulky volume of a whole optical add-drop multiplexer, so that the performance is poor; furthermore, add-drop multiplexing of each light needs to be implemented by one three-port apparatus, so that the costs are high when more channels exist.
The AWG technology mainly uses a waveguide technology to allow the light of different wavelengths to form energy concentration at different side emission positions after passing through different paths, thereby separating the light of different wavelengths. However, the optical add-drop multiplexer is sensitive to temperature, has poor performance parameters, and requires an electrically controlled heater; and furthermore, the fabrication of an AWG chip is expensive, so that the costs are high.